Have artificial discs been approved by the fda yet?

Yes. Several have been approved by the fda including but limited to charitÉ™ artificial disc, prodisc®-l total disc replacement, and prestige® cervical disc. If you feel you are a candidate for a disc replacement, you should talk to your pcp and to a spine surgeon.
Yes. Several, and recently ldr has received a two level approval for its disc, mobi-c.